From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NaV3g-0003k1-Ra for qemu-devel@nongnu.org; Thu, 28 Jan 2010 09:09:20 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NaV3b-0003gK-Dd for qemu-devel@nongnu.org; Thu, 28 Jan 2010 09:09:20 -0500 Received: from [199.232.76.173] (port=50323 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NaV3a-0003fn-O0 for qemu-devel@nongnu.org; Thu, 28 Jan 2010 09:09:14 -0500 Received: from e35.co.us.ibm.com ([32.97.110.153]:52239) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1NaV3a-0002d1-5Z for qemu-devel@nongnu.org; Thu, 28 Jan 2010 09:09:14 -0500 Received: from d03relay05.boulder.ibm.com (d03relay05.boulder.ibm.com [9.17.195.107]) by e35.co.us.ibm.com (8.14.3/8.13.1) with ESMTP id o0SDtAws018138 for ; Thu, 28 Jan 2010 06:55:10 -0700 Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by d03relay05.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o0SE93RT033534 for ; Thu, 28 Jan 2010 07:09:04 -0700 Received: from d03av05.boulder.ibm.com (loopback [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o0SE92Rt006574 for ; Thu, 28 Jan 2010 07:09:03 -0700 Message-ID: <4B619A7C.5090606@linux.vnet.ibm.com> Date: Thu, 28 Jan 2010 08:09:00 -0600 From: Anthony Liguori MIME-Version: 1.0 References: <20100128124327.GA32288@lst.de> In-Reply-To: <20100128124327.GA32288@lst.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: future of the virtio-blk serial number support List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christoph Hellwig Cc: john cooper , Christian Borntraeger , Rusty Russell , qemu-devel@nongnu.org, "Michael S. Tsirkin" On 01/28/2010 06:43 AM, Christoph Hellwig wrote: > Back iSeptember 2007 Michael made the serial number support in qemu > optional and off by default, and in October 2009 Rusty reverted the > Linux virtio-blk support for it. Given that I can't find support in > any other virtio implementation that makes the feature look essentially > dead. > > How should we proceed with adding more fields to struct virtio_blk_config? > I would suggest removing the identity field, declaring > VIRTIO_BLK_F_IDENTIFY officially deprecated and adding the new fields > directly after blk_size again, maybe with a comment that these new > features can't be advertized together with VIRTIO_BLK_F_IDENTIFY. > > I need to add a new optiomal_io_size field soon to support the block > topology information when using virtio which is quite important when > using RAID arrays as backend, and I'd prefer to do it in a way that's > compatibly with the PCI spec. > Sounds good to me. IDENTIFY is basically impossible to implement in it's current form with virtio-pci. We should put something in the spec mentioning that config space is limited and large values should not be placed in it. Instead, implementations should use a control ring queue to pass large data sets. Regards, Anthony Liguori